Redistricting created two new competitive districts, 65 and 66 in Gallatin County, both favoring Biden.

[4] Districts where the margin of victory was under 10%: [6][5] Incumbent Republican Steve Gunderson was ineligible to run for re-election due to term limits.

He originally intended to run in the Republican primary for Montana State Auditor, but withdrew.

Incumbent Democrat Dave Fern was ineligible to run for re-election due to term limits, and will now represent Senate District 2.

Incumbent Republican Denley Loge was ineligible to run for re-election due to term limits, and will now represent Senate District 45.

Incumbent Republican Ross Fitzgerald was ineligible to run for re-election due to term limits.

Incumbent Republican Fred Anderson was ineligible to run for re-election due to term limits.

Incumbent Republican Lola Sheldon-Galloway was ineligible to run for re-election due to term limits.

He ran in the Republican primary for District 20 due to redistricting, but lost.

Steve Fitzpatrick was the incumbent Majority Leader in the Senate, but was ineligible to run for re-election due to term limits.

Incumbent Republican Edward Butcher had represented the district since 2023, but did not file for re-election.

He ran in the Republican primary for District 78 due to redistricting, but lost.

Incumbent Democrat Jonathan Windy Boy has represented the district since 2017, and was ineligible to run for re-election due to term limits.

Incumbent Republican Casey Knudsen had represented the district since 2017, and was ineligible to run for re-election due to term limits.

Incumbent Democrat Sharon Stewart-Peregoy had represented the district since 2017 and was ineligible for re-election due to term limits.

Incumbent Republican Naarah Hastings had represented the district since 2023, but did not file for re-election.

Incumbent Republican Terry Moore had represented the district since 2019, but did not file for re-election.

Incumbent Republican Sue Vinton had represented the district since 2017 and was ineligible for re-election due to term limits.

Incumbent Democrat Laurie Bishop had represented the district since 2017 and was ineligible to run for re-election due to term limits.

Incumbent Democrat Jim Hamilton had represented the district since 2017 and was ineligible to run for re-election due to term limits.

Incumbent Democrat Alice Buckley had represented the district since 2021 but did not file for re-election.

She ran in the Republican primary for District 68 due to redistricting, but lost.

Incumbent Republican Tom Welch had represented the district since 2017, and was ineligible to run for re-election due to term limits.

She ran in the Republican primary to continue representing District 85, but lost.

Incumbent Republican Mike Hopkins had represented the district since 2017, and was ineligible to run for re-election due to term limits.